This application relates generally to oil drilling and production. More specifically, this application relates to containment of leaks during oil drilling, production, and completion processes.
There are a number of different types of structures that are used in oil drilling, but there are certain common features. For example, a common approach is to drill a borehole (typically between 5 and 50 inches in diameter) into the earth with a drilling rig that rotates a drill string with a bit attached. Casing sections of steel pipe having a diameter smaller than the borehole are place into the borehole, and cement may be used between the outside of the casing and the borehole itself. This casing provides structural integrity to the borehole and may also isolate potentially dangerous high-pressure zones from each other and from the surface. It is common to drill deeper by using a sequence of smaller bits with progressively smaller casings.
The cased borehole is completed by making perforations in the portion of the casing in the oil-production zone, thereby providing a path for the oil to flow from the surrounding rock into production tubing. Other structures such as sand screens or gravel packs may additionally be used, as known to those of skill in the art. While many sites have sufficient natural pressure in the subsurface reservoir for the oil to flow to the surface, other sites require the use of additional structures such as downhole pumps, gas lifts, or surface pump jacks.
One of the risks involved with these techniques for oil production is the potential for structures to leak. Natural pressures on the structures, both underground and aboveground, can cause damage. Over time, even small leaks can result in the escape of considerable amounts of oil that not only affects production volume but may also cause damage to the local environment by producing pools of leaked oil.
Traditional methods for addressing this potential for leaks have made use of concrete culvert pipes, but there are a number of long-term costs and safety issues associated with such methods. For example, difficulties with culvert pipes include the potential for soil and groundwater contamination and present a difficult work environment for onsite workers.
There is accordingly a need in the art for methods and systems that prevent the escape of leaked oil in oil-production processes.